The invention relates to a device for clamping bags around the exit end of the filling neck of a system for filling bags. A known system of this type is the 3200 Series Slidell-Matic System manufactured by Slidell (USA), which includes a bag clamping device. A system of this type is particularly suitable for handling bags with side folds, in which case the bags are pulled over the filling neck with the side folds already folded and are then taken over by a second pair of clamps so that during the subsequent filling operation, the side folds in the region of the bag opening do not open up. Consequently, there is no need for the side folds to be refolded and realigned after the filling operation to permit subsequent closing of the bag; in particular, there is no need for folding over the bag edge prior to the final sewing or gluing operation.
Such bag clamping devices are also advantageous for simple flat bags, especially bags with so-called "pinch-tops", in which the upper bag edge is also folded over for closing purposes. In this case, too, it is essential for the side fold of the bag to remain in its accurate position, i.e., the two bag walls have to be held one against the other in the region of the side edges.
With the above-mentioned device, the bags, after having been slipped on to the filling neck, are held by the first pairs of clamps on the surfaces of the expanding flaps and are fixed by the second pairs of clamps in the region of their side edges at some distance in front of the end faces. Subsequently, suction ports are introduced into the open bag opening in front of the end faces of the filling neck the purpose of such ports being to suck out any air and, in consequence, dust displaced during the filling process. For this purpose, the second pairs of clamps are moved close to the suction ports. Close contact with the planar surfaces of the suction ports and of the expanding flaps is ensured by the resulting vacuum. However, the said devices are also advantageous for simple flat bags, especially bags with so-called "pinch-tops", in the case of which the upper bag edge is also folded over for closing purposes. In this case, too, it is essential for the side fold of the bag to remain in its accurate position, i.e., the two bag walls have to be held one against the other in the region of the side edges.
With the above-mentioned device, the bags, after having been slipped on to the filling neck, are held by the first pairs of clamps on the surfaces of the expanding flaps and are fixed by the second pairs of clamps in the region of their side edges at some distance away from the end faces. Subsequently, suction ports are introduced into the bag opening in front of the end faces of the filling neck, the purpose of such ports being to suck out any air and, in consequence, dust displaced during the filling process. For this purpose, the second pairs of clamps are moved close to the suction ports. Close contact with the planar surfaces of the suction ports and of the expanding flaps is ensured by the vacuum created by the suction ports.